1. Field of the Invention
The present invention relates to a connector, and more particularly to a connector having a male housing and a female housing and which provides optical emitter/sensor means for identifying the engagement and type of the connector while providing electrical isolation between a connected electrical transmission device and the identification means.
2. Description of the Prior Art
Connectors having a male housing, a female housing, and means to confirm proper fitting between the housings are disclosed in Japanese Laid Open Utility Model Publication No. 53-95187, U.S. Pat. No. 4,925,402, and U.S. Pat. No. 4,902,244.
The connector of Japanese Laid Open Utility Model Publication No. 53-95187 includes a light emitting element, a light detecting device, and a light reflecting plate. The female housing is provided with first and second passageways to allow light from the light emitting element to reach the reflecting plate and allow the reflected light to reach the light detecting device. The first and second passageways are inclined with respect to each other such that light will only be reflected onto the light detecting device if the male and female housings are properly fitted. The connector is provided with an opto-electronic converter element for converting the reflected light incident to the light detecting device to an electric signal. This connector configuration has two significant drawbacks. The complex configuration of light emitting element, light detecting device, reflector, and inclined light passageways (which must be formed in the female housing) increases manufacturing costs. Furthermore, it is not possible to identify the type of connector or any related information using this scheme.
The connector of U.S. Pat. No. 4,925,402 includes a longitudinal guide channel formed in the female housing for receiving a guide member formed on the male housing. The guide member has apertures formed therein and the guide channel has corresponding apertures such that when the male and female housings are properly fitted together, the apertures of each housing will be aligned. An optical detector is used to measure the fitting condition between the housings by moving it the length of the guide channel. The optical detector is provided with an opto-electronic converter which produces a signal for analysis by a computer. This connector configuration allows a determination of the degree of incongruity between the housings and the type of connector. The connector has a significant drawback in that it requires a manual step by the user in addition to engaging the male and female housings, namely moving the optical detector across the guide channel.
The connector of U.S. Pat. No. 4,902,244 includes slits of predetermined widths and spacings formed in a sidewall of the female housing and a black surface on the male housing. When the housings are properly fitted, a bar code is formed by the black surface shown through the slits. By passing a bar code reader across the slits, the type of connector and the condition of the fit between the housings can simultaneously be determined. This method also suffers from the drawback that a separate action by the user is required, namely the implementation of the bar code reader.
None of the prior art provide an economical and reliable method of detecting a connector's engagement and type which does not require manual human interaction. There exists a need for such a connector which also provides electrical isolation between the connected device and the detecting means. In the United States and in Europe, there are safety requirements that different types of connectors from the various countries be detectable with a high degree of voltage isolation. An example is International Standard IEC 950. As a result, metallic identification systems cannot be used.
An example of the need for such a connector is found in lBM's ISDN Basic Rate Adapter which requires the identification of a country's specific cable and/or diagnostic connector/plug type. This identification is needed to insure that the correct software option is used with each cable and connector/plug configuration without any manual human interaction. To comply with certain safety requirements, voltage isolation of 3.75 kilovolts (kV) must be provided between the common carrier transmission circuits and the internal electronics of the adapter circuits. This requirement is intended to protect the computer and the computer user from power surges transmitted through a transmission cable due to, for example, a lightning strike.